Research On The Vertical Spatial Zoning And Ore-Bearing Layers Recognition Of Sandstone Uranium Deposit

Uranium resources as the national energy-strategic resources are one of the major needs of national military,defense industry,energy development,and orderly growth of the national economy.Sandstone uranium deposits are the most promising among all types of uranium deposits.Epigenetic uranium is accompanied by the erosion,hydrolysis and weathering of rocks.Uranium element migration and enrichment are both required relatively special basin depositional conditions and structural background.It makes the mineralization process of sandstone uranium have a certain spatial selective distribution and has the stratification and zoning characteristics in the vertical spatial distribution.Therefore,this characteristics in the vertical space of sandstone uranium deposits have certain theoretical guiding significance for the study of mineralization law and resource prediction.In this paper,we foucs on a typical sandstone uranium deposit,Daying uranium deposit in northern Ordos Basin.Using geophysical borehole logging quantitative data and chronological information qualitative data to conduct in-depth analysis of key issues in uranium mineralization,uranium anomalies and the distribution and variation characteristics of uranium elements in vertical space.Then,the spatial vertical two-dimensional zoning characteristics and three-dimensional visualization of sandstone uranium deposits are presented.The two-dimensional abnormal zone zoning and three-dimensional abnormal area delineated of ore-bearing layers recognition are achieved.These provide research methods and theoretical basis for vertical spatial distribution,regional mineralization characteristics and resource forecast of sandstone uranium deposit in Ordos Basin.The proposed spatial vertical zoning and ore-bearing layers recognition of sandstone uranium models belong to the study of nonlinear models in the complex environment of sandstone uranium deposits.It has the characteristics of large samples,many variables,fusion of qualitative data and quantitative data,etc.,which is a kind of typical sandstone uranium deposit geological data analysis.As an exploration and attempt to nonlinear methods study for different types,different scales and different resolutions.The three sandstone uranium deposits methods proposed in this paper are summarized as follows:(1)Spatial spectral metric-based spatical vertical zoning method of sandstone uranium deposits.Based on the structural characteristics,geological background and sedimentary environment of the basin,a spatial spectral metric is established with Fourier and power spectrum density.The Gamma measurement exposure rate(n C/kg·h)curve data is used for trial calculation.The identification and extraction of the ore-bearing layers in the vertical space.According to the depth of the identified ore-bearing layers,the spatial vertical two-dimensional zoning distribution characteristics and spatial vertical three-dimensional abnormal visualization are given.The identification and delineation of the abnormal section of the ore-bearing layers in sandstone uranium deposit is completed.(2)Spatial scale analysis and spatial spectral metric-based spatial vertical zoning method of sandstone uranium deposits.In this method,various logging data(including gamma measurement exposure rate(n C/kg·h),quantitative gamma measurement exposure rate(n C/kg·h),aperture(mm),natural Potential(mv),apparent resistivity(?·m),density(g/cm~3),etc.)are comprehensively analyzed by using regression analysis.Then the ore-bearing layers are identified and extracted in the vertical space combined with the spatial spectral metric.According to the depth position of the ore-bearing layers,the spatial vertical two-dimensional zoning distribution characteristics and spatial vertical three-dimensional abnormal visualization are completed.Compared with the spatial spectral metric method,it can provide comprehensive factors analysis for the uranium mineralization,and make up for the shortcomings of a single gamma irradiation rate curve in actual sandstone uranium deposit detection.(3)Generalized relevant analysis and spatial spectral metric-based spatial vertical zoning method of sandstone uranium deposits.In this method,the chronological qualitative data is used to perform restrictive analysis on the quantitative data of multiple logging curves.Then the chronological data and multiple logging curves are processed combining with the relevant component analysis and spatial spectral metric method.According to the ore-bearing layers identification and extraction results,the spatial vertical two-dimensional zoning distribution and the spatial vertical three-dimensional abnormal visualization are completed.Compared with the above two proposed methods with the known mineralization information,the utilization of chronological qualitative data in the vertical zoning of sandstone uranium deposits,can make the the ore-bearing layers identification and extraction more accurate.Sandstone uranium deposits are a relatively special mineral resources,which can be enriched into ore under the special geological backgrounds.In this paper,various metallogenic factors of sandstone uranium deposits are comprehensive considered,and a series of spatial vertical zoning methods based on different types of data(borehole logging data and chronological information data)are proposed for accurate ore-bearing layers identification.Furthermore,it provides theoretical basis and technical methods for the establishment of the spatial vertical zoning system of sandstone uranium basins and the prediction of sandstone uranium resources.